Zum Einfluß von Ameisensäure, Calciumformiat und Natriumhydrogencarbonat auf pH-Wert, Trockenmassegehalt, Konzentration an Carbonsäuren und Ammoniak in verschiedenen Segmenten des Gastrointestinaltraktes

Use of Organic Acid Mixtures Containing 2-Hydroxy-4-(Methylthio) Butanoic Acid (HMTBa) to Mitigate Salmonella enterica, Shiga Toxin-Producing Escherichia coli (STEC) and Aspergillus flavus in Pet Food Kibbles

Post-processing operations of extruded pet food kibbles involve coating the product with fats and flavorings. These processes increase the risk for cross-contamination with food-borne pathogens such as Salmonella and Shiga toxin-producing Escherichia coli (STEC), and mycotoxin-producing molds such as Aspergillus spp. after the thermal kill step. In this study, the antimicrobial effects of two types of organic acid mixtures containing 2-hydroxy-4-(methylthio) butanoic acid (HMTBa), Activate DA™ and Activate US WD-MAX™, against Salmonella enterica, STEC and Aspergillus flavus when used as a coating on pet food kibbles were evaluated. Using canola oil and dry dog digest as fat and flavor coatings, the efficacy of Activate DA (HMTBa + fumaric acid + benzoic acid) at 0%, 1% and 2%, and Activate US WD-MAX (HMTBa + lactic acid + phosphoric acid) at 0%, 0.5% and 1% was tested on kibbles inoculated with a cocktail of S. enterica serovars (Enteritidis, Heidelberg and Typhimurium) or Shiga toxin-producing E. coli (STEC) serovars (O121, and O26) at 37 °C for 0, 12, 24, 48, 72 h, 30 and 60 days. Similarly, their efficacy was tested against A. flavus at 25 °C for 0, 3, 7, 14, 21, 28 and 35 days. Activate DA at 2% and Activate US WD-MAX at 1% reduced Salmonella counts by ~3 logs after 12 h and 4-4.6 logs after 24 h. Similarly, STEC counts were reduced by ~2 logs and 3 logs after 12 h and 24 h, respectively. Levels of A. flavus did not vary up to 7 days, and afterwards started to decline by >2 logs in 14 days, and up to 3.8-log reduction in 28 days for Activate DA and Activate US WD-MAX at 2% and 1%, respectively. The results suggest that the use of these organic acid mixtures containing HMTBa during kibble coating may mitigate post-processing enteric pathogen and mold contamination in pet food kibbles, with Activate US WD-MAX being effective at a lower concentration (0.5-1%) compared to Activate DA.

Organic acids for performance enhancement in pig diets

Organic acids and their salts appear to be potential alternatives to prophylactic in-feed antibiotics and growth promoters in order to improve the performance of weaned piglets, fattening pigs and reproductive sows, although their growth-promoting effects are generally less than that of antibiotics. Based on an analysis of published data, the growth-promoting effect of formates, fumarates and citrates did not differ in weaned piglets. In fattening pigs, formates were the most effective followed by fumarates, whereas propionates did not improve growth performance. These acids improved the feedgain ratio of both weaned piglets and fattening pigs. In weaned piglets, the growth-promoting effects of dietary organic acids appear to depend greatly on their influence on feed intake. In sows, organic acids may have anti-agalactia properties. Successful application of organic acids in the diets for pigs requires an understanding of their modes of action. It is generally considered that dietary organic acids or their salts lower gastric pH, resulting in increased activity of proteolytic enzymes and gastric retention time, and thus improved protein digestion. Reduced gastric pH and increased retention time have been difficult to demonstrate, whereas improved apparent ileal digestibilities of protein and amino acids have been observed with growing pigs, but not in weaned piglets. Organic acids may influence mucosal morphology, as well as stimulate pancreatic secretions, and they also serve as substrates in intermediary metabolism. These may further contribute to improved digestion, absorption and retention of many dietary nutrients. Organic acid supplementation reduces dietary buffering capacity, which is expected to slow down the proliferation and|or colonization of undesirable microbes, e.g. Escherichia coli, in the gastro-ileal region. However, reduced scouring has been observed in only a few studies. As performance responses to dietary organic acids in pigs often varies, more specific studies are necessary to elucidate an explanation.

Effect of benzoic acid on growth performance, nutrient digestibility, nitrogen balance, gastrointestinal microflora and parameters of microbial metabolism in piglets

In order to investigate the effects of benzoic acid on growth performance, nutrient digestibility, nitrogen balance and gastrointestinal microflora of piglets, we conducted a performance experiment and a separate balance study. The performance experiment involved four different dietary treatments: (1) basal diet (negative control); (2) basal diet supplemented with benzoic acid at 5 g/kg; (3) basal diet supplemented with benzoic acid at 10 g/kg; (4) basal diet supplemented with potassium diformate at 12 g/kg. Each dietary treatment was assigned to nine replicate groups, each consisting of two piglets. Live weight, daily weight gain, feed intake and feed conversion ratio were monitored as performance parameters over a 35-day period. Supplementation of the diet with benzoic acid resulted in a dose-dependent increase in feed intake and body weight gain and an improved feed conversion ratio. Piglets fed the diet supplemented with benzoic acid at 10 g/kg outperformed the control piglets in mean feed intake, body weight gain and feed conversion ratio by 9%, 15% and 6% respectively. Growth performance of the piglets fed the diet with benzoic acid at 10 g/kg was similar to that of piglets fed the diet supplemented with potassium diformate. In the balance experiment three groups of six piglets each were fed either a control diet or diets supplemented with benzoic acid at 5 or 10 g/kg respectively. Benzoic acid did not significantly affect nutrient digestibility but increased nitrogen retention. Piglets fed the diets supplemented with benzoic acid at 5 or 10 g/kg retained 5% and 6% more nitrogen, respectively, than control piglets. Supplementation of benzoic acid did not influence the pH value or the concentration of ammonia in the gastrointestinal tract but reduced the number of bacteria in the digesta. In the stomach the number of total aerobic, total anaerobic, lactic acid forming and gram-negative bacteria was reduced; in the duodenum the presence of benzoic acid reduced the number of gram-negative bacteria and in the ileum the number of total aerobic bacteria in a dose-dependent manner. Benzoic acid also considerably reduced the concentration of acetic acid in the duodenum. In conclusion, the data of this study suggest that benzoic acid exerts strong antimicrobial effects in the gastrointestinal tract of piglets and therefore enhances growth performance and nitrogen retention.

[The nutritive efficiency of Bacillus cereus as a probiotic in the raising of piglets. 1. Effect on the growth parameters and gastrointestinal environment]

In an experiment with 4 x 12 piglets the probiotic effect of the Bacillus cereus strain FH 1457 S on the performance and changes in the gastrointestinal tract was studied. Beside a negative control the feed was supplemented with 10(7), 10(8) and 10(9) CFU Bacillus cereus/kg. The experiment included two feeding periods, whereby in the first a prestarter and in the second a piglet rearing feed was administrated ad libitum with the animals kept individually in cages. Over the whole feeding trial the piglets with the additions of 10(7), 10(8) und 10(9) CFU Bacillus cereus/kg feed showed higher daily weight gains of 9.5%, 11.1% and 8.6% with an increased feed consumption of 11.1%, 11.0% and 7.9%. The feed conversion rate was not influenced by the additions. In the first period daily weight gains were increased by 8.9%, 14.7% and 7.8%, the feed consumption in this period was 10.2%, 12.1% and 7.2% higher than in the control group. The addition of 10(8) CFU Bacillus cereus had a significantly higher daily weight gain in the first period compared to the control and the feed conversion rate was improved by 2.4%. In the second period the daily weight gains were increased by 9.9%, 8.9% and 9.1%, the feed consumption by 11.4%, 10.5% and 8.8% because of Bacillus cereus addition to the feed. The frequency of diarrhea was not influenced by the treatments. In each Bacillus cereus dosage the concentrations of ammonia, lactate and volatile fatty acids in small intestine contents were mostly diminished. In caecum contents the concentrations of acetic and propionic acid were decreased in the groups supplemented with Bacillus cereus.